Digital Holographic Microscopy (DHM) is a technique which allows a recording of a 3D sample or object without the need of scanning the sample layer-by-layer. Numerous parameters related to the scanned object or sample can be obtained by digital holographic microscopy. Digital holographic microscopy has been proven to be particularly useful for analyzing living transparent objects such as cells or samples containing cells. Such samples have for a long time been studied by means of light microscopy, such as fluorescence, confocal of phase contrast microscopy. However, the latter techniques often require treatment of the cells, such as fixation of the cells and/or staining with markers or fluorescent dyes. As such, these treatments might result in loss of information stored in the cell. Moreover, these treatments are time consuming and require specific training and knowledge of personnel. Digital holographic microscopy omits the necessity of treating the cells prior to analysis. Furthermore, DHM allows for the analysis of cells in a liquid sample, again omitting certain handlings, such as for instance depositing cells on a microscopic plate in order to achieve a thin layer of cells. As such, DHM is an emerging new tool used for cell sample analysis, for instance in the diagnostic field.
In order to study a liquid cell sample by DHM, one has to provide the cell sample in a sample vial, optimized for use in conjunction of a DHM. The purpose is to provide a vial that allows accurate phase and amplitude information of a cell sample and its cells, through use of a DHM. WO 2009 154 558 discloses a method for analyzing cells in a sample through DHM and a sample vial to be used in conjunction with a digital holographic microscope. The sample vial is specifically designed as a culture flask for growing cells, and is hence less suited to be used as a sample vial for diagnostic purpose. As samples obtained for diagnostic purpose often have a variable cell concentration, different from sample to sample, it is often difficult to obtain the right cell concentration or in case of samples comprising few cells, to analyze an adequate amount of cells in order to come to a reliable and statistically significant analysis of the sample. Furthermore, as cells in a suspension obtained for diagnostic purpose are freely floating in the sample, it is not always easy to obtain a qualitative image and analysis of the cells in the sample. It is the object of the current invention to provide a solution for at least one of the problems mentioned above.